1. Field of the Invention
The present invention relates generally to bolts and more particularly is concerned with an apparatus for supporting illuminated signs on walls, providing means for supplying electricity to the signs and providing a built-in grounding means for the sign through the bolt itself.
2. Description of the Prior Art
Display signs have been used by merchants for years to display their business name, merchandise or whatever they wish to display. As technology advanced, merchants began using illuminated signs. A typical illuminated sign is composed of a U-shaped bracket, also known as a raceway, which supports the neon tube inside the raceway. The open end of the raceway is covered with translucent plastic or fabric. Illuminated signs are often hung on the walls of buildings by suitable support means well known in the art. A problem existed in supporting the sign and at the same time running the electrical wires from inside the building through the wall to the sign safely and still providing a grounding means for the sign. This problem has plagued the electrical conduit business for years.
One attempt to solve this problem is illustrated in FIG. 1 wherein is shown a prior art apparatus currently in use comprising a hollow plastic bolt 1 having a threaded shaft 2. The bolt further has a head 3 rigidly attached on one end, a spacer nut 4 and a lock nut 5 all threadably engaged on the shaft 2. A hollow cable adapter 6 is provided for threadably engaging into the end of the shaft 2 by means of a threaded bore 7. The hollow cable adapter 6 has an extending shaft 8 with ridges 9 disposed thereon for threadably engaging into the armored cable 10. The electrical wire is then run from the building through the hollow shaft and into the sign as illustrated in FIG. 2.
While the above described apparatus has been used to meet the needs of the electrical conduit business, it has some serious drawbacks. One major drawback is the fact that the spacer nut 4 has to be screwed all the way up the shaft 2 to the head 3. Normally these plastic bolts are very long, and this process of screwing the spacer nut 4 all the way up the shaft is a very time consuming task and is also very tiring on one's hands. A second disadvantage of the prior art is that the electrical wires have to be first inserted through the conduit connector and then through the flexible metal conduit, which requires more time. Another major drawback of the prior art is that the hollow cable adapter 6 does not securely fit within the end of the flexible metal conduit 10 to form a tight and rigid connection. Perhaps the biggest disadvantage of the prior art is that there are no means to provide grounding of the electrical sign with the bolt. Underwriters' Laboratory requires all signs to be grounded directly back to the source of power. The prior art does not teach this. In practice, a separate wire is run from the sign to the flexible conduit, which is not acceptable by Underwriters' Laboratory or any electrical code.
Consequently, a need exists for improvements in the prior art which will overcome these drawbacks.